The development of scientific investigations in solid-state physics in the universities of the USSR

Conclusions Scientific research work in solid-state physics along the lines laid down by the Joint Section of the Scientific and Technical Council of the Ministry of Higher and Secondary Specialized Education USSR is being carried out in more than 60 colleges in the Soviet Union; 25 of these are leading executive and co-executive organs for the most important topics of the Five Year Plan (1966–70). However, these figures do not fully represent the contribution made by the higher educational establishments to the development of science in our country. The higher schools participate indirectly, through the training of personnel, in scientific work in the academic and industrial institutes, and many promising scientific ideas, first conceived in the higher schools, are adopted by the Academy of Sciences and are further developed within its walls.This review of the scientific work of the colleges does not pretend to embrace all the problems of solid-state physics; the authors may have overlooked particular works or allowed some inaccuracy in formulation to remain; the completeness of the review, however, also depended on the material available to the Joint Committee. The reader can find additional material in reports by Academicians G. V. Kurdyumov, S. T. Konobeevskii, S. V. Vonsovskii, and L. F. Vereshchagin, the Corresponding Members AS USSR I. M. Lifshits and B. K. Vainshtein, Doctors A. A. Smirnov, E. I. Kondorskii, and others, to the Jubilee Session of the Council of the USSR Academy of Sciences on solid-state physics (April 1967).An objective estimate of Soviet scientific work, including that of the higher schools, is given in the proceedings of numerous international congresses, conferences, and meetings which take place with the active and effective participation of Soviet scientists. A broad view of the achievements in the field of solid-state physics can be obtained from the Seventh International Crystallographic Congress held in Moscow in July 1966. One-third of the 960 papers read at the Congress were the work of Soviet scientists; the contribution of the colleges amounted to 40% of all Soviet work. These statistics, which are also confirmed by an analysis of the scientific papers in physics journals, appear to reflect correctly the quantitative contribution of the higher schools to the working out of scientific problems of solid-state physics in the USSR.At the same time the scientific standard of the best college works is not inferior to that of the academic institutes in the Soviet Union or in the West, despite the fact that they are carried out under more restricted conditions. Soviet scientists can confidently hold their own in many fields of solid-state physics including those of the theory of symmetry, the theory of electron structure, and the theory of the physical properties of crystals. Soviet experimental investigations in the fields of magnetism and ferroelectricity and the strength, plasticity, and dislocation structure of crystals are not inferior to the best examples abroad, although all branches of study are not equally represented in their entirety in the USSR.A serious misgiving arises, however, on account of the lag in the theoretical and applied work on the growth of single crystals, which is holding back the development of solid-state physics as a whole. One would think that capital investments in this field would completely justify themselves and make it possible to achieve new scientific advances in solid-state physics in the USSR.     

Operator-based Floquet theory in solid-state NMR

This article reviews the application of operator-based Floquet theory in solid-state NMR. Basic expressions for calculating effective Hamiltonians based on van Vleck perturbation theory are reviewed for problems with a single frequency or multiple incommensurate frequencies. Such a treatment allows calculation of effective Hamiltonians for resonant and non-resonant problems. Examples from literature are given for single-mode to triple-mode Floquet problems, covering a wide range of applications in solid-state NMR under magic-angle spinning and radio-frequency irradiation of a single nucleus or multiple nuclei.     

Mercury and beyond: diode-pumped solid-state lasers for inertial fusion energy

We have begun building the Mercury laser system as the first in a series of new generation diode-pumped solid-state lasers for inertial fusion research. Mercury will integrate three key technologies: diodes, crystals and gas cooling, within a unique laser architecture that is scalable to kilojoules and megajoule energy levels for fusion energy applications. The primary near-term performance goals include 10% electrical efficiencies at 10 Hz and 100 J with a 2–10 ns pulse length at 1.047 μ m wavelength. When completed, Mercury will allow rep-rated target experiments with multiple chambers for high energy density physics research.     

Multivariate analysis methods in physics

In this article, a review of multivariate methods based on statistical learning is given. Several popular multivariate methods useful in high-energy physics analysis are discussed. Selected examples from current research in particle physics are discussed, both from online trigger selection and from off-line analysis. In addition, statistical learning methods, not yet applied in particle physics, are presented and some new applications are suggested. The text was submitted by the author in English.     

Fausto Fumi and the emergence of solid-state physics in Italy

Summary This paper surveys the early history of solid-state physics, particularly the period 1949–58, and the seminal role of Fausto Fumi in establishing the first school of modern solid-state physics in Italy. In honour of Prof. Fausto Fumi on the occasion of his retirement from teaching.     

Recent progress and new challenges in isospin physics with heavy-ion reactions

The ultimate goal of studying isospin physics via heavy-ion reactions with neutron-rich, stable and/or radioactive nuclei is to explore the isospin dependence of in-medium nuclear effective interactions and the equation of state of neutron-rich nuclear matter, particularly the isospin-dependent term in the equation of state, i.e., the density dependence of the symmetry energy. Because of its great importance for understanding many phenomena in both nuclear physics and astrophysics, the study of the density dependence of the nuclear symmetry energy has been the main focus of the intermediate-energy heavy-ion physics community during the last decade, and significant progress has been achieved both experimentally and theoretically. In particular, a number of phenomena or observables have been identified as sensitive probes to the density dependence of nuclear symmetry energy. Experimental studies have confirmed some of these interesting isospin-dependent effects and allowed us to constrain relatively stringently the symmetry energy at sub-saturation densities. The impact of this constrained density dependence of the symmetry energy on the properties of neutron stars have also been studied, and they were found to be very useful for the astrophysical community. With new opportunities provided by the various radioactive beam facilities being constructed around the world, the study of isospin physics is expected to remain one of the forefront research areas in nuclear physics. In this report, we review the major progress achieved during the last decade in isospin physics with heavy ion reactions and discuss future challenges to the most important issues in this field.     

Uncoupled photonic band gaps

We theoretically investigated the symmetry properties of the modes in two-dimensional square lattice photonic crystals in order to study phenomena that would enable new frontiers in the applications of photonic crystals. Using group theory, symmetry analysis of the photonic crystals bands has been done. Particular attention was given to the search for the uncoupled B modes that cannot be excited by the external plane wave because they are symmetry forbidden. The existence of the uncoupled modes enabled to define new physics phenomena: uncoupled photonic band gaps. For the frequency ranges inside the uncoupled photonic band gaps, zero transmission is obtained. Therefore, there are two different types of photonic gaps in the photonic crystals: photonic band gaps and uncoupled photonic band gaps. The appearance of uncoupled photonic band gaps in photonic crystals could at least improve the application of the existing photonic materials and structures or even enable the usage of new ones for devices like waveguides, filters, and lasers.     

The state of ferroelectric physics

Conclusions It can be concluded from this review that ferroelectric physics is one of the actively expanding branches of solid-state physics. The concepts of states related to the ferroelectric one, e.g., the ferroelastic state, have broadened significantly. Within this field successful studies are being performed of such general questions as phase transitions, subsystem interactions, i.e., the interaction of different quasiparticles, and other nonlinear processes. In ferroelectric semiconductors the interaction of charge carriers with spontaneous polarization is being studied, while in Seignette ferromagnetics the interaction of magnetic and electric subsystems is under investigation. Nonlinear phenomena are given special study in the phase transition region.A number of new interesting phenomena have been discovered in ferroelectric studies recently: phonon echo, photovoltaic effect, autolocalization of charge carriers in the phase transition region, etc. Many new classes of ferroelectrics have been discovered, thus demonstrating the broad extent of the ferroelectric state in nature. Apparently, certain organic compounds and liquid crystals may be classified as ferroelectrics. Results of ferroelectric studies are widely used in the national economy.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 5–39, January, 1979.     

Morphology of critical nuclei in solid-state phase transformations

Predicting the shape of a critical nucleus in solids has been a long-standing problem in solid-state phase transformations. We show that a diffuse-interface approach together with a minimax algorithm is able to predict the critical nucleus morphology in elastically anisotropic solids without a priori assumptions. We demonstrate the possibility of nonconvex surfaces for critical nuclei. It is found that strong elastic energy contributions may lead to critical nuclei whose point group symmetry is below the crystalline symmetries of both the new and the parent phases.     

Cosmic rays and particle physics

The study of high energy cosmic rays is a diversified field of observational and phenomenological physics addressing questions ranging from shock acceleration of charged particles in various astrophysical objects, via transport properties through galactic and extragalactic space, to questions of dark matter, and even to those of particle physics beyond the Standard Model including processes taking place in the earliest moments of our Universe. After decades of mostly independent evolution of nuclear, particle and high energy cosmic ray physics we find ourselves entering a symbiotic era of these fields of research. Some examples of interrelations will be given from the perspective of modern Particle-Astrophysics and new major experiments will briefly be sketched.     

Optoelectronic Devices: Design,Modeling, and Simulation,by Xun Li

A historical survey of the development of solid-state detectors is given, and it is shown why semiconductor detectors are superior to the earlier crystal counters. The physical processes which occur during the detection of nuclear radiation in a solid-state device are considered in detail, and the merits of the reverse-biased semiconductor junction in silicon or germanium are set out. Factors which determine the energy resolution of such a detector are analysed, and also the effects of radiation damage. The preparation of such detectors is not treated in detail, but the physical principles on which the important types of detector depend are described. The final section surveys the field of applications of solid-state detectors in nuclear physics, radiochemical analysis, space research, medicine and biology.     

Flavor and LHC searches for new physics

Uncovering the physics of electroweak symmetry breaking (EWSB) is the raison-d’etre of the LHC. Flavor questions, it would seem, are of minor relevance for this quest, apart from their role in constraining the possible structure of EWSB physics. In this short review article, we outline, using flavor-dependent slepton physics as an example, how flavor can affect both searches for supersymmetry, and future measurements aimed at understanding the nature of any new discoveries. If the production cross-sections for supersymmetry are relatively low, as indicated by the fact that it has not revealed itself yet in standard searches, the usual assumptions about the superpartner spectra need rethinking. Furthermore, one must consider more intricate searches, such as lepton-based searches, which could be susceptible to flavor effects. We start by reviewing the flavor structure of existing frameworks for mediating supersymmetry breaking, emphasizing flavor-dependent models proposed recently. We use the kinematic endpoints of invariant mass distributions to demonstrate how flavor dependence can impact both searches for supersymmetry and the Inverse Problem. We also discuss methods for measuring small-mass splittings and mixings at the LHC, both in models with a neutralino LSP and in models with a charged slepton (N)LSP.     

Crystal field theory and the Shubnikov point groups

Two pieces of theory which have so far remained unconnected, crystal field theory and the theory of corepresentations of non-unitary groups, are brought together here for the study of the splitting of atomic energy levels in a crystalline field with the symmetry of one of the magnetic (Shubnikov) point groups. The cases of the various possible relative strengths of the crystalline field and of spin-orbit coupling are considered.

Tables are presented which enable the splitting of any atomic energy level to be obtained very easily in a crystalline field with the symmetry of any one of the 58 magnetic point groups. Examples of the use of these tables are given.

A discussion is given of the relevance of Kramers' theorem to the energy levels of electrons in surroundings with the symmetry of any one of the 58 magnetic point groups.     

Developments in high energy theory

This non-technical review article is aimed at readers with some physics background, including beginning research students. It provides a panoramic view of the main theoretical developments in high energy physics since its inception more than half a century ago, a period in which experiments have spanned an enormous range of energies, theories have been developed leading up to the Standard Model, and proposals — including the radical paradigm of String Theory — have been made to go beyond the Standard Model. The list of references provided here is not intended to properly credit all original work but rather to supply the reader with a few pointers to the literature, specifically highlighting work done by Indian authors.     

Plasma physics in Latin America

The status of plasma physics in Latin America is reviewed. The review surveys the history and present situation of the regional activities in high-temperature plasma research, plasma astrophysics, and technological applications of plasma physics. In particular, it presents data on the trends of evolution of scientific staff, annual operating budget, and publication rate for the major Latin American plasma groups during the decade 1983-1992. On this basis, the prospects for further growth and the potential for regional contribution to the mainstream of international plasma research and development are discussed     

NUCLEAR MAGNETIC RESONANCE IN FERROMAGNETS AND ANTIFERROMAGNETS

Abstract

The development of solid-state physics and, in particular, the investigation of magnetoordered crystals require the use of experimental methods that will yield information about the spatial distribution of electron and spin densities and about different branches of the energy spectrum in crystals. These data together with data on crystal symmetry provide important information that can be used to develop theories of the magnetoordered state. Nuclear magnetic resonance NMR) is one of the most fruitful methods for studying spatial distributions of local magnetic fields and spin density, electron-nuclear interactions, and the temperature dependence of magnetic moments. The nuclei are excellent natural probes that allow direct measurement of the properties of electron and spin systems of crystals. Of course, such measurements can only be made on nuclei that have magnetic moments.     

Efficient and stable wireless power transfer based on the non-Hermitian physics

As one of the most attractive non-radiative power transfer mechanisms without cables,efficient magnetic resonance wireless power transfer(WPT)in the near field has been extensively developed in recent years,and promoted a variety of practical applications,such as mobile phones,medical implant devices and electric vehicles.However,the physical mechanism behind some key limitations of the resonance WPT,such as frequency splitting and size-dependent efficiency,is not very clear under the widely used circuit model.Here,we review the recently developed efficient and stable resonance WPT based on non-Hermitian physics,which starts from a completely different avenue(utilizing loss and gain)to introduce novel functionalities to the resonance WPT.From the perspective of non-Hermitian photonics,the coherent and incoherent effects compete and coexist in the WPT system,and the weak stable of energy transfer mainly comes from the broken phase associated with the phase transition of parity-time symmetry.Based on this basic physical framework,some optimization schemes are proposed,including using nonlinear effect,using bound states in the continuum,or resorting to the system with high-order parity-time symmetry.Moreover,the combination of non-Hermitian physics and topological photonics in multi-coil system also provides a versatile platform for long-range robust WPT with topological protection.Therefore,the non-Hermitian physics can not only exactly predict the main results of current WPT systems,but also provide new ways to solve the difficulties of previous designs.